Compaction behaviour of urea treated crop residues in feed blocks

The crop residues (wheat straw, paddy straw, mustard straw and sugarcane bagasse) were treated with 4% urea and stacked for 21 days. Stack was opened and 15% molasses was added and moisture level was raised to 15–17%. The material was thoroughly mixed and blocks were made in the electrically operated hydraulic press. Paddy straw had minimum (P<0.01) loose bulk density as compared to other crop residues. On densification as feed blocks, there was 2.78, 3.28, 2.85 and 2.87 times increase (P<0.01) in density in untreated wheat straw, paddy straw, mustard straw and sugar cane bagasse based blocks. The post compression expansion among blocks made of different crop residues was highest (P<0.01) in wheat straw (12.62%) and lowest in sugarcane bagasse (6.89%) based feed blocks. Paddy straw blocks were least (P<0.01) durable (42.54%) in comparison to the blocks of other crop residues. Urea treatment increased the loose bulk density of the crop residues from 74.00 to 78.59 kg/m³, on densification the density increased from 2.85 to 3.02 times resulting in decreased (P<0.01) post compression expansion 9.11 vs 7.15 per cent and increased durability 55.50 vs 74.38 per cent. The total cost of urea treatment of crop residues was worked out to be Rs. 24.23 per quintal, while the total cost incurred on densification of wheat straw paddy straw mustard straw and sugarcane bagasse was Rs.36.03 35.95, 36.24 and 37.88/quintal, respectively. Feed blocks made up of urea treated crop residue had higher (P<0.05) CP ADF and cellulose contents and lower (P<0.05) NFE NDF and hemicellulose contents than those made up of untreated crop residues.